The ‘Intrastate-Trade-Restriction’ Defence in Commerce-clause Challenges of State-imposed Restrictions on Water Exports to Neighbouring States

A state-imposed restriction on water exports to neighbouring states runs the risk of exciting constitutional challenge as an impermissible barrier to interstate trade under the dormant commerce clause. Recent federal court cases are reviewed to determine whether a state can avoid, or survive, such a challenge to a water export restriction by contending that its statutes restrict intrastate water transfers to a similar extent. These cases demonstrate that states have not been successful with this defence. We therefore recommend that states not impose, or maintain, restrictions on intrastate water transfers for the purpose of keeping the option open on such a defence.